REACTION OF METALS AND NON-METALS WITH WATER

Metals react with water and produce metal oxide and hydrogen gas

Metal + water——> metal oxide +hydrogen 

Metal oxide produced here if soluble in the water further produces metal hydroxide 

Metal oxide + water ——> metal hydroxide 

Sodium and potassium react violently with water. During reaction with water lot of heat is produced along with hydrogen so they catch fire when put in water (hydrogen is a flammable gas)

WATCH THE VIDEO SHOWING REACTION OF SODIUM WITH WATER

Metals like iron react with water very slowly only,  because the reactivity of different metals is different 

Generally, non-metals don't react with water. But they are reactive with air, so some highly reactive non-metals like phosphorus are stored in water(if phosphorus is kept open in the atmosphere it reacts with air and catches fire)